fs/read_write.c - kernel/msm-4.9 - Gitiles

 /*
  *  linux/fs/read_write.c
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  */

 #include <linux/slab.h>
 #include <linux/stat.h>
 #include <linux/fcntl.h>
 #include <linux/file.h>
 #include <linux/uio.h>
 #include <linux/smp_lock.h>
 #include <linux/fsnotify.h>
 #include <linux/security.h>
 #include <linux/module.h>
 #include <linux/syscalls.h>

 #include <asm/uaccess.h>
 #include <asm/unistd.h>

 struct file_operations generic_ro_fops = {
 	.llseek		= generic_file_llseek,
 	.read		= generic_file_read,
 	.mmap		= generic_file_readonly_mmap,
 	.sendfile	= generic_file_sendfile,
 };

 EXPORT_SYMBOL(generic_ro_fops);

 loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
 {
 	long long retval;
 	struct inode *inode = file->f_mapping->host;

 	down(&inode->i_sem);
 	switch (origin) {
 		case 2:
 			offset += inode->i_size;
 			break;
 		case 1:
 			offset += file->f_pos;
 	}
 	retval = -EINVAL;
 	if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {
 		if (offset != file->f_pos) {
 			file->f_pos = offset;
 			file->f_version = 0;
 		}
 		retval = offset;
 	}
 	up(&inode->i_sem);
 	return retval;
 }

 EXPORT_SYMBOL(generic_file_llseek);

 loff_t remote_llseek(struct file *file, loff_t offset, int origin)
 {
 	long long retval;

 	lock_kernel();
 	switch (origin) {
 		case 2:
 			offset += i_size_read(file->f_dentry->d_inode);
 			break;
 		case 1:
 			offset += file->f_pos;
 	}
 	retval = -EINVAL;
 	if (offset>=0 && offset<=file->f_dentry->d_inode->i_sb->s_maxbytes) {
 		if (offset != file->f_pos) {
 			file->f_pos = offset;
 			file->f_version = 0;
 		}
 		retval = offset;
 	}
 	unlock_kernel();
 	return retval;
 }
 EXPORT_SYMBOL(remote_llseek);

 loff_t no_llseek(struct file *file, loff_t offset, int origin)
 {
 	return -ESPIPE;
 }
 EXPORT_SYMBOL(no_llseek);

 loff_t default_llseek(struct file *file, loff_t offset, int origin)
 {
 	long long retval;

 	lock_kernel();
 	switch (origin) {
 		case 2:
 			offset += i_size_read(file->f_dentry->d_inode);
 			break;
 		case 1:
 			offset += file->f_pos;
 	}
 	retval = -EINVAL;
 	if (offset >= 0) {
 		if (offset != file->f_pos) {
 			file->f_pos = offset;
 			file->f_version = 0;
 		}
 		retval = offset;
 	}
 	unlock_kernel();
 	return retval;
 }
 EXPORT_SYMBOL(default_llseek);

 loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
 {
 	loff_t (*fn)(struct file *, loff_t, int);

 	fn = no_llseek;
 	if (file->f_mode & FMODE_LSEEK) {
 		fn = default_llseek;
 		if (file->f_op && file->f_op->llseek)
 			fn = file->f_op->llseek;
 	}
 	return fn(file, offset, origin);
 }
 EXPORT_SYMBOL(vfs_llseek);

 asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
 {
 	off_t retval;
 	struct file * file;
 	int fput_needed;

 	retval = -EBADF;
 	file = fget_light(fd, &fput_needed);
 	if (!file)
 		goto bad;

 	retval = -EINVAL;
 	if (origin <= 2) {
 		loff_t res = vfs_llseek(file, offset, origin);
 		retval = res;
 		if (res != (loff_t)retval)
 			retval = -EOVERFLOW;	/* LFS: should only happen on 32 bit platforms */
 	}
 	fput_light(file, fput_needed);
 bad:
 	return retval;
 }

 #ifdef __ARCH_WANT_SYS_LLSEEK
 asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
 			   unsigned long offset_low, loff_t __user * result,
 			   unsigned int origin)
 {
 	int retval;
 	struct file * file;
 	loff_t offset;
 	int fput_needed;

 	retval = -EBADF;
 	file = fget_light(fd, &fput_needed);
 	if (!file)
 		goto bad;

 	retval = -EINVAL;
 	if (origin > 2)
 		goto out_putf;

 	offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low,
 			origin);

 	retval = (int)offset;
 	if (offset >= 0) {
 		retval = -EFAULT;
 		if (!copy_to_user(result, &offset, sizeof(offset)))
 			retval = 0;
 	}
 out_putf:
 	fput_light(file, fput_needed);
 bad:
 	return retval;
 }
 #endif


 int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count)
 {
 	struct inode *inode;
 	loff_t pos;

 	if (unlikely(count > INT_MAX))
 		goto Einval;
 	pos = *ppos;
 	if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
 		goto Einval;

 	inode = file->f_dentry->d_inode;
 	if (inode->i_flock && MANDATORY_LOCK(inode))
 		return locks_mandatory_area(read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, inode, file, pos, count);
 	return 0;

 Einval:
 	return -EINVAL;
 }

 static void wait_on_retry_sync_kiocb(struct kiocb *iocb)
 {
 	set_current_state(TASK_UNINTERRUPTIBLE);
 	if (!kiocbIsKicked(iocb))
 		schedule();
 	else
 		kiocbClearKicked(iocb);
 	__set_current_state(TASK_RUNNING);
 }

 ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
 {
 	struct kiocb kiocb;
 	ssize_t ret;

 	init_sync_kiocb(&kiocb, filp);
 	kiocb.ki_pos = *ppos;
 	while (-EIOCBRETRY ==
 		(ret = filp->f_op->aio_read(&kiocb, buf, len, kiocb.ki_pos)))
 		wait_on_retry_sync_kiocb(&kiocb);

 	if (-EIOCBQUEUED == ret)
 		ret = wait_on_sync_kiocb(&kiocb);
 	*ppos = kiocb.ki_pos;
 	return ret;
 }

 EXPORT_SYMBOL(do_sync_read);

 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
 {
 	ssize_t ret;

 	if (!(file->f_mode & FMODE_READ))
 		return -EBADF;
 	if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read))
 		return -EINVAL;
 	if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
 		return -EFAULT;

 	ret = rw_verify_area(READ, file, pos, count);
 	if (!ret) {
 		ret = security_file_permission (file, MAY_READ);
 		if (!ret) {
 			if (file->f_op->read)
 				ret = file->f_op->read(file, buf, count, pos);
 			else
 				ret = do_sync_read(file, buf, count, pos);
 			if (ret > 0) {
 				fsnotify_access(file->f_dentry);
 				current->rchar += ret;
 			}
 			current->syscr++;
 		}
 	}

 	return ret;
 }

 EXPORT_SYMBOL(vfs_read);

 ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
 {
 	struct kiocb kiocb;
 	ssize_t ret;

 	init_sync_kiocb(&kiocb, filp);
 	kiocb.ki_pos = *ppos;
 	while (-EIOCBRETRY ==
 	       (ret = filp->f_op->aio_write(&kiocb, buf, len, kiocb.ki_pos)))
 		wait_on_retry_sync_kiocb(&kiocb);

 	if (-EIOCBQUEUED == ret)
 		ret = wait_on_sync_kiocb(&kiocb);
 	*ppos = kiocb.ki_pos;
 	return ret;
 }

 EXPORT_SYMBOL(do_sync_write);

 ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
 {
 	ssize_t ret;

 	if (!(file->f_mode & FMODE_WRITE))
 		return -EBADF;
 	if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write))
 		return -EINVAL;
 	if (unlikely(!access_ok(VERIFY_READ, buf, count)))
 		return -EFAULT;

 	ret = rw_verify_area(WRITE, file, pos, count);
 	if (!ret) {
 		ret = security_file_permission (file, MAY_WRITE);
 		if (!ret) {
 			if (file->f_op->write)
 				ret = file->f_op->write(file, buf, count, pos);
 			else
 				ret = do_sync_write(file, buf, count, pos);
 			if (ret > 0) {
 				fsnotify_modify(file->f_dentry);
 				current->wchar += ret;
 			}
 			current->syscw++;
 		}
 	}

 	return ret;
 }

 EXPORT_SYMBOL(vfs_write);

 static inline loff_t file_pos_read(struct file *file)
 {
 	return file->f_pos;
 }

 static inline void file_pos_write(struct file *file, loff_t pos)
 {
 	file->f_pos = pos;
 }

 asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
 {
 	struct file *file;
 	ssize_t ret = -EBADF;
 	int fput_needed;

 	file = fget_light(fd, &fput_needed);
 	if (file) {
 		loff_t pos = file_pos_read(file);
 		ret = vfs_read(file, buf, count, &pos);
 		file_pos_write(file, pos);
 		fput_light(file, fput_needed);
 	}

 	return ret;
 }
 EXPORT_SYMBOL_GPL(sys_read);

 asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count)
 {
 	struct file *file;
 	ssize_t ret = -EBADF;
 	int fput_needed;

 	file = fget_light(fd, &fput_needed);
 	if (file) {
 		loff_t pos = file_pos_read(file);
 		ret = vfs_write(file, buf, count, &pos);
 		file_pos_write(file, pos);
 		fput_light(file, fput_needed);
 	}

 	return ret;
 }

 asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
 			     size_t count, loff_t pos)
 {
 	struct file *file;
 	ssize_t ret = -EBADF;
 	int fput_needed;

 	if (pos < 0)
 		return -EINVAL;

 	file = fget_light(fd, &fput_needed);
 	if (file) {
 		ret = -ESPIPE;
 		if (file->f_mode & FMODE_PREAD)
 			ret = vfs_read(file, buf, count, &pos);
 		fput_light(file, fput_needed);
 	}

 	return ret;
 }

 asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf,
 			      size_t count, loff_t pos)
 {
 	struct file *file;
 	ssize_t ret = -EBADF;
 	int fput_needed;

 	if (pos < 0)
 		return -EINVAL;

 	file = fget_light(fd, &fput_needed);
 	if (file) {
 		ret = -ESPIPE;
 		if (file->f_mode & FMODE_PWRITE)
 			ret = vfs_write(file, buf, count, &pos);
 		fput_light(file, fput_needed);
 	}

 	return ret;
 }

 /*
  * Reduce an iovec's length in-place.  Return the resulting number of segments
  */
 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
 {
 	unsigned long seg = 0;
 	size_t len = 0;

 	while (seg < nr_segs) {
 		seg++;
 		if (len + iov->iov_len >= to) {
 			iov->iov_len = to - len;
 			break;
 		}
 		len += iov->iov_len;
 		iov++;
 	}
 	return seg;
 }

 EXPORT_SYMBOL(iov_shorten);

 /* A write operation does a read from user space and vice versa */
 #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)

 static ssize_t do_readv_writev(int type, struct file *file,
 			       const struct iovec __user * uvector,
 			       unsigned long nr_segs, loff_t *pos)
 {
 	typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
 	typedef ssize_t (*iov_fn_t)(struct file *, const struct iovec *, unsigned long, loff_t *);

 	size_t tot_len;
 	struct iovec iovstack[UIO_FASTIOV];
 	struct iovec *iov=iovstack, *vector;
 	ssize_t ret;
 	int seg;
 	io_fn_t fn;
 	iov_fn_t fnv;

 	/*
 	 * SuS says "The readv() function *may* fail if the iovcnt argument
 	 * was less than or equal to 0, or greater than {IOV_MAX}.  Linux has
 	 * traditionally returned zero for zero segments, so...
 	 */
 	ret = 0;
 	if (nr_segs == 0)
 		goto out;

 	/*
 	 * First get the "struct iovec" from user memory and
 	 * verify all the pointers
 	 */
 	ret = -EINVAL;
 	if ((nr_segs > UIO_MAXIOV) || (nr_segs <= 0))
 		goto out;
 	if (!file->f_op)
 		goto out;
 	if (nr_segs > UIO_FASTIOV) {
 		ret = -ENOMEM;
 		iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
 		if (!iov)
 			goto out;
 	}
 	ret = -EFAULT;
 	if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector)))
 		goto out;

 	/*
 	 * Single unix specification:
 	 * We should -EINVAL if an element length is not >= 0 and fitting an
 	 * ssize_t.  The total length is fitting an ssize_t
 	 *
 	 * Be careful here because iov_len is a size_t not an ssize_t
 	 */
 	tot_len = 0;
 	ret = -EINVAL;
 	for (seg = 0; seg < nr_segs; seg++) {
 		void __user *buf = iov[seg].iov_base;
 		ssize_t len = (ssize_t)iov[seg].iov_len;

 		if (len < 0)	/* size_t not fitting an ssize_t .. */
 			goto out;
 		if (unlikely(!access_ok(vrfy_dir(type), buf, len)))
 			goto Efault;
 		tot_len += len;
 		if ((ssize_t)tot_len < 0) /* maths overflow on the ssize_t */
 			goto out;
 	}
 	if (tot_len == 0) {
 		ret = 0;
 		goto out;
 	}

 	ret = rw_verify_area(type, file, pos, tot_len);
 	if (ret)
 		goto out;

 	fnv = NULL;
 	if (type == READ) {
 		fn = file->f_op->read;
 		fnv = file->f_op->readv;
 	} else {
 		fn = (io_fn_t)file->f_op->write;
 		fnv = file->f_op->writev;
 	}
 	if (fnv) {
 		ret = fnv(file, iov, nr_segs, pos);
 		goto out;
 	}

 	/* Do it by hand, with file-ops */
 	ret = 0;
 	vector = iov;
 	while (nr_segs > 0) {
 		void __user * base;
 		size_t len;
 		ssize_t nr;

 		base = vector->iov_base;
 		len = vector->iov_len;
 		vector++;
 		nr_segs--;

 		nr = fn(file, base, len, pos);

 		if (nr < 0) {
 			if (!ret) ret = nr;
 			break;
 		}
 		ret += nr;
 		if (nr != len)
 			break;
 	}
 out:
 	if (iov != iovstack)
 		kfree(iov);
 	if ((ret + (type == READ)) > 0) {
 		if (type == READ)
 			fsnotify_access(file->f_dentry);
 		else
 			fsnotify_modify(file->f_dentry);
 	}
 	return ret;
 Efault:
 	ret = -EFAULT;
 	goto out;
 }

 ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
 		  unsigned long vlen, loff_t *pos)
 {
 	if (!(file->f_mode & FMODE_READ))
 		return -EBADF;
 	if (!file->f_op || (!file->f_op->readv && !file->f_op->read))
 		return -EINVAL;

 	return do_readv_writev(READ, file, vec, vlen, pos);
 }

 EXPORT_SYMBOL(vfs_readv);

 ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
 		   unsigned long vlen, loff_t *pos)
 {
 	if (!(file->f_mode & FMODE_WRITE))
 		return -EBADF;
 	if (!file->f_op || (!file->f_op->writev && !file->f_op->write))
 		return -EINVAL;

 	return do_readv_writev(WRITE, file, vec, vlen, pos);
 }

 EXPORT_SYMBOL(vfs_writev);

 asmlinkage ssize_t
 sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
 {
 	struct file *file;
 	ssize_t ret = -EBADF;
 	int fput_needed;

 	file = fget_light(fd, &fput_needed);
 	if (file) {
 		loff_t pos = file_pos_read(file);
 		ret = vfs_readv(file, vec, vlen, &pos);
 		file_pos_write(file, pos);
 		fput_light(file, fput_needed);
 	}

 	if (ret > 0)
 		current->rchar += ret;
 	current->syscr++;
 	return ret;
 }

 asmlinkage ssize_t
 sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
 {
 	struct file *file;
 	ssize_t ret = -EBADF;
 	int fput_needed;

 	file = fget_light(fd, &fput_needed);
 	if (file) {
 		loff_t pos = file_pos_read(file);
 		ret = vfs_writev(file, vec, vlen, &pos);
 		file_pos_write(file, pos);
 		fput_light(file, fput_needed);
 	}

 	if (ret > 0)
 		current->wchar += ret;
 	current->syscw++;
 	return ret;
 }

 static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
 			   size_t count, loff_t max)
 {
 	struct file * in_file, * out_file;
 	struct inode * in_inode, * out_inode;
 	loff_t pos;
 	ssize_t retval;
 	int fput_needed_in, fput_needed_out;

 	/*
 	 * Get input file, and verify that it is ok..
 	 */
 	retval = -EBADF;
 	in_file = fget_light(in_fd, &fput_needed_in);
 	if (!in_file)
 		goto out;
 	if (!(in_file->f_mode & FMODE_READ))
 		goto fput_in;
 	retval = -EINVAL;
 	in_inode = in_file->f_dentry->d_inode;
 	if (!in_inode)
 		goto fput_in;
 	if (!in_file->f_op || !in_file->f_op->sendfile)
 		goto fput_in;
 	retval = -ESPIPE;
 	if (!ppos)
 		ppos = &in_file->f_pos;
 	else
 		if (!(in_file->f_mode & FMODE_PREAD))
 			goto fput_in;
 	retval = rw_verify_area(READ, in_file, ppos, count);
 	if (retval)
 		goto fput_in;

 	retval = security_file_permission (in_file, MAY_READ);
 	if (retval)
 		goto fput_in;

 	/*
 	 * Get output file, and verify that it is ok..
 	 */
 	retval = -EBADF;
 	out_file = fget_light(out_fd, &fput_needed_out);
 	if (!out_file)
 		goto fput_in;
 	if (!(out_file->f_mode & FMODE_WRITE))
 		goto fput_out;
 	retval = -EINVAL;
 	if (!out_file->f_op || !out_file->f_op->sendpage)
 		goto fput_out;
 	out_inode = out_file->f_dentry->d_inode;
 	retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count);
 	if (retval)
 		goto fput_out;

 	retval = security_file_permission (out_file, MAY_WRITE);
 	if (retval)
 		goto fput_out;

 	if (!max)
 		max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);

 	pos = *ppos;
 	retval = -EINVAL;
 	if (unlikely(pos < 0))
 		goto fput_out;
 	if (unlikely(pos + count > max)) {
 		retval = -EOVERFLOW;
 		if (pos >= max)
 			goto fput_out;
 		count = max - pos;
 	}

 	retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);

 	if (retval > 0) {
 		current->rchar += retval;
 		current->wchar += retval;
 	}
 	current->syscr++;
 	current->syscw++;

 	if (*ppos > max)
 		retval = -EOVERFLOW;

 fput_out:
 	fput_light(out_file, fput_needed_out);
 fput_in:
 	fput_light(in_file, fput_needed_in);
 out:
 	return retval;
 }

 asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t __user *offset, size_t count)
 {
 	loff_t pos;
 	off_t off;
 	ssize_t ret;

 	if (offset) {
 		if (unlikely(get_user(off, offset)))
 			return -EFAULT;
 		pos = off;
 		ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
 		if (unlikely(put_user(pos, offset)))
 			return -EFAULT;
 		return ret;
 	}

 	return do_sendfile(out_fd, in_fd, NULL, count, 0);
 }

 asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t __user *offset, size_t count)
 {
 	loff_t pos;
 	ssize_t ret;

 	if (offset) {
 		if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
 			return -EFAULT;
 		ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
 		if (unlikely(put_user(pos, offset)))
 			return -EFAULT;
 		return ret;
 	}

 	return do_sendfile(out_fd, in_fd, NULL, count, 0);
 }
	/*
	* linux/fs/read_write.c
	*
	* Copyright (C) 1991, 1992 Linus Torvalds
	*/

	#include <linux/slab.h>
	#include <linux/stat.h>
	#include <linux/fcntl.h>
	#include <linux/file.h>
	#include <linux/uio.h>
	#include <linux/smp_lock.h>
	#include <linux/fsnotify.h>
	#include <linux/security.h>
	#include <linux/module.h>
	#include <linux/syscalls.h>

	#include <asm/uaccess.h>
	#include <asm/unistd.h>

	struct file_operations generic_ro_fops = {
	.llseek = generic_file_llseek,
	.read = generic_file_read,
	.mmap = generic_file_readonly_mmap,
	.sendfile = generic_file_sendfile,
	};

	EXPORT_SYMBOL(generic_ro_fops);

	loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
	{
	long long retval;
	struct inode *inode = file->f_mapping->host;

	down(&inode->i_sem);
	switch (origin) {
	case 2:
	offset += inode->i_size;
	break;
	case 1:
	offset += file->f_pos;
	}
	retval = -EINVAL;
	if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {
	if (offset != file->f_pos) {
	file->f_pos = offset;
	file->f_version = 0;
	}
	retval = offset;
	}
	up(&inode->i_sem);
	return retval;
	}

	EXPORT_SYMBOL(generic_file_llseek);

	loff_t remote_llseek(struct file *file, loff_t offset, int origin)
	{
	long long retval;

	lock_kernel();
	switch (origin) {
	case 2:
	offset += i_size_read(file->f_dentry->d_inode);
	break;
	case 1:
	offset += file->f_pos;
	}
	retval = -EINVAL;
	if (offset>=0 && offset<=file->f_dentry->d_inode->i_sb->s_maxbytes) {
	if (offset != file->f_pos) {
	file->f_pos = offset;
	file->f_version = 0;
	}
	retval = offset;
	}
	unlock_kernel();
	return retval;
	}
	EXPORT_SYMBOL(remote_llseek);

	loff_t no_llseek(struct file *file, loff_t offset, int origin)
	{
	return -ESPIPE;
	}
	EXPORT_SYMBOL(no_llseek);

	loff_t default_llseek(struct file *file, loff_t offset, int origin)
	{
	long long retval;

	lock_kernel();
	switch (origin) {
	case 2:
	offset += i_size_read(file->f_dentry->d_inode);
	break;
	case 1:
	offset += file->f_pos;
	}
	retval = -EINVAL;
	if (offset >= 0) {
	if (offset != file->f_pos) {
	file->f_pos = offset;
	file->f_version = 0;
	}
	retval = offset;
	}
	unlock_kernel();
	return retval;
	}
	EXPORT_SYMBOL(default_llseek);

	loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
	{
	loff_t (fn)(struct file , loff_t, int);

	fn = no_llseek;
	if (file->f_mode & FMODE_LSEEK) {
	fn = default_llseek;
	if (file->f_op && file->f_op->llseek)
	fn = file->f_op->llseek;
	}
	return fn(file, offset, origin);
	}
	EXPORT_SYMBOL(vfs_llseek);

	asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
	{
	off_t retval;
	struct file * file;
	int fput_needed;

	retval = -EBADF;
	file = fget_light(fd, &fput_needed);
	if (!file)
	goto bad;

	retval = -EINVAL;
	if (origin <= 2) {
	loff_t res = vfs_llseek(file, offset, origin);
	retval = res;
	if (res != (loff_t)retval)
	retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
	}
	fput_light(file, fput_needed);
	bad:
	return retval;
	}

	#ifdef __ARCH_WANT_SYS_LLSEEK
	asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
	unsigned long offset_low, loff_t __user * result,
	unsigned int origin)
	{
	int retval;
	struct file * file;
	loff_t offset;
	int fput_needed;

	retval = -EBADF;
	file = fget_light(fd, &fput_needed);
	if (!file)
	goto bad;

	retval = -EINVAL;
	if (origin > 2)
	goto out_putf;

	offset = vfs_llseek(file, ((loff_t) offset_high << 32) \| offset_low,
	origin);

	retval = (int)offset;
	if (offset >= 0) {
	retval = -EFAULT;
	if (!copy_to_user(result, &offset, sizeof(offset)))
	retval = 0;
	}
	out_putf:
	fput_light(file, fput_needed);
	bad:
	return retval;
	}
	#endif


	int rw_verify_area(int read_write, struct file file, loff_t ppos, size_t count)
	{
	struct inode *inode;
	loff_t pos;

	if (unlikely(count > INT_MAX))
	goto Einval;
	pos = *ppos;
	if (unlikely((pos < 0) \|\| (loff_t) (pos + count) < 0))
	goto Einval;

	inode = file->f_dentry->d_inode;
	if (inode->i_flock && MANDATORY_LOCK(inode))
	return locks_mandatory_area(read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, inode, file, pos, count);
	return 0;

	Einval:
	return -EINVAL;
	}

	static void wait_on_retry_sync_kiocb(struct kiocb *iocb)
	{
	set_current_state(TASK_UNINTERRUPTIBLE);
	if (!kiocbIsKicked(iocb))
	schedule();
	else
	kiocbClearKicked(iocb);
	__set_current_state(TASK_RUNNING);
	}

	ssize_t do_sync_read(struct file filp, char __user buf, size_t len, loff_t *ppos)
	{
	struct kiocb kiocb;
	ssize_t ret;

	init_sync_kiocb(&kiocb, filp);
	kiocb.ki_pos = *ppos;
	while (-EIOCBRETRY ==
	(ret = filp->f_op->aio_read(&kiocb, buf, len, kiocb.ki_pos)))
	wait_on_retry_sync_kiocb(&kiocb);

	if (-EIOCBQUEUED == ret)
	ret = wait_on_sync_kiocb(&kiocb);
	*ppos = kiocb.ki_pos;
	return ret;
	}

	EXPORT_SYMBOL(do_sync_read);

	ssize_t vfs_read(struct file file, char __user buf, size_t count, loff_t *pos)
	{
	ssize_t ret;

	if (!(file->f_mode & FMODE_READ))
	return -EBADF;
	if (!file->f_op \|\| (!file->f_op->read && !file->f_op->aio_read))
	return -EINVAL;
	if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
	return -EFAULT;

	ret = rw_verify_area(READ, file, pos, count);
	if (!ret) {
	ret = security_file_permission (file, MAY_READ);
	if (!ret) {
	if (file->f_op->read)
	ret = file->f_op->read(file, buf, count, pos);
	else
	ret = do_sync_read(file, buf, count, pos);
	if (ret > 0) {
	fsnotify_access(file->f_dentry);
	current->rchar += ret;
	}
	current->syscr++;
	}
	}

	return ret;
	}

	EXPORT_SYMBOL(vfs_read);

	ssize_t do_sync_write(struct file filp, const char __user buf, size_t len, loff_t *ppos)
	{
	struct kiocb kiocb;
	ssize_t ret;

	init_sync_kiocb(&kiocb, filp);
	kiocb.ki_pos = *ppos;
	while (-EIOCBRETRY ==
	(ret = filp->f_op->aio_write(&kiocb, buf, len, kiocb.ki_pos)))
	wait_on_retry_sync_kiocb(&kiocb);

	if (-EIOCBQUEUED == ret)
	ret = wait_on_sync_kiocb(&kiocb);
	*ppos = kiocb.ki_pos;
	return ret;
	}

	EXPORT_SYMBOL(do_sync_write);

	ssize_t vfs_write(struct file file, const char __user buf, size_t count, loff_t *pos)
	{
	ssize_t ret;

	if (!(file->f_mode & FMODE_WRITE))
	return -EBADF;
	if (!file->f_op \|\| (!file->f_op->write && !file->f_op->aio_write))
	return -EINVAL;
	if (unlikely(!access_ok(VERIFY_READ, buf, count)))
	return -EFAULT;

	ret = rw_verify_area(WRITE, file, pos, count);
	if (!ret) {
	ret = security_file_permission (file, MAY_WRITE);
	if (!ret) {
	if (file->f_op->write)
	ret = file->f_op->write(file, buf, count, pos);
	else
	ret = do_sync_write(file, buf, count, pos);
	if (ret > 0) {
	fsnotify_modify(file->f_dentry);
	current->wchar += ret;
	}
	current->syscw++;
	}
	}

	return ret;
	}

	EXPORT_SYMBOL(vfs_write);

	static inline loff_t file_pos_read(struct file *file)
	{
	return file->f_pos;
	}

	static inline void file_pos_write(struct file *file, loff_t pos)
	{
	file->f_pos = pos;
	}

	asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
	{
	struct file *file;
	ssize_t ret = -EBADF;
	int fput_needed;

	file = fget_light(fd, &fput_needed);
	if (file) {
	loff_t pos = file_pos_read(file);
	ret = vfs_read(file, buf, count, &pos);
	file_pos_write(file, pos);
	fput_light(file, fput_needed);
	}

	return ret;
	}
	EXPORT_SYMBOL_GPL(sys_read);

	asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count)
	{
	struct file *file;
	ssize_t ret = -EBADF;
	int fput_needed;

	file = fget_light(fd, &fput_needed);
	if (file) {
	loff_t pos = file_pos_read(file);
	ret = vfs_write(file, buf, count, &pos);
	file_pos_write(file, pos);
	fput_light(file, fput_needed);
	}

	return ret;
	}

	asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
	size_t count, loff_t pos)
	{
	struct file *file;
	ssize_t ret = -EBADF;
	int fput_needed;

	if (pos < 0)
	return -EINVAL;

	file = fget_light(fd, &fput_needed);
	if (file) {
	ret = -ESPIPE;
	if (file->f_mode & FMODE_PREAD)
	ret = vfs_read(file, buf, count, &pos);
	fput_light(file, fput_needed);
	}

	return ret;
	}

	asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf,
	size_t count, loff_t pos)
	{
	struct file *file;
	ssize_t ret = -EBADF;
	int fput_needed;

	if (pos < 0)
	return -EINVAL;

	file = fget_light(fd, &fput_needed);
	if (file) {
	ret = -ESPIPE;
	if (file->f_mode & FMODE_PWRITE)
	ret = vfs_write(file, buf, count, &pos);
	fput_light(file, fput_needed);
	}

	return ret;
	}

	/*
	* Reduce an iovec's length in-place. Return the resulting number of segments
	*/
	unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
	{
	unsigned long seg = 0;
	size_t len = 0;

	while (seg < nr_segs) {
	seg++;
	if (len + iov->iov_len >= to) {
	iov->iov_len = to - len;
	break;
	}
	len += iov->iov_len;
	iov++;
	}
	return seg;
	}

	EXPORT_SYMBOL(iov_shorten);

	/* A write operation does a read from user space and vice versa */
	#define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)

	static ssize_t do_readv_writev(int type, struct file *file,
	const struct iovec __user * uvector,
	unsigned long nr_segs, loff_t *pos)
	{
	typedef ssize_t (io_fn_t)(struct file , char __user , size_t, loff_t );
	typedef ssize_t (iov_fn_t)(struct file , const struct iovec , unsigned long, loff_t );

	size_t tot_len;
	struct iovec iovstack[UIO_FASTIOV];
	struct iovec iov=iovstack, vector;
	ssize_t ret;
	int seg;
	io_fn_t fn;
	iov_fn_t fnv;

	/*
	* SuS says "The readv() function may fail if the iovcnt argument
	* was less than or equal to 0, or greater than {IOV_MAX}. Linux has
	* traditionally returned zero for zero segments, so...
	*/
	ret = 0;
	if (nr_segs == 0)
	goto out;

	/*
	* First get the "struct iovec" from user memory and
	* verify all the pointers
	*/
	ret = -EINVAL;
	if ((nr_segs > UIO_MAXIOV) \|\| (nr_segs <= 0))
	goto out;
	if (!file->f_op)
	goto out;
	if (nr_segs > UIO_FASTIOV) {
	ret = -ENOMEM;
	iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
	if (!iov)
	goto out;
	}
	ret = -EFAULT;
	if (copy_from_user(iov, uvector, nr_segssizeof(uvector)))
	goto out;

	/*
	* Single unix specification:
	* We should -EINVAL if an element length is not >= 0 and fitting an
	* ssize_t. The total length is fitting an ssize_t
	*
	* Be careful here because iov_len is a size_t not an ssize_t
	*/
	tot_len = 0;
	ret = -EINVAL;
	for (seg = 0; seg < nr_segs; seg++) {
	void __user *buf = iov[seg].iov_base;
	ssize_t len = (ssize_t)iov[seg].iov_len;

	if (len < 0) /* size_t not fitting an ssize_t .. */
	goto out;
	if (unlikely(!access_ok(vrfy_dir(type), buf, len)))
	goto Efault;
	tot_len += len;
	if ((ssize_t)tot_len < 0) /* maths overflow on the ssize_t */
	goto out;
	}
	if (tot_len == 0) {
	ret = 0;
	goto out;
	}

	ret = rw_verify_area(type, file, pos, tot_len);
	if (ret)
	goto out;

	fnv = NULL;
	if (type == READ) {
	fn = file->f_op->read;
	fnv = file->f_op->readv;
	} else {
	fn = (io_fn_t)file->f_op->write;
	fnv = file->f_op->writev;
	}
	if (fnv) {
	ret = fnv(file, iov, nr_segs, pos);
	goto out;
	}

	/* Do it by hand, with file-ops */
	ret = 0;
	vector = iov;
	while (nr_segs > 0) {
	void __user * base;
	size_t len;
	ssize_t nr;

	base = vector->iov_base;
	len = vector->iov_len;
	vector++;
	nr_segs--;

	nr = fn(file, base, len, pos);

	if (nr < 0) {
	if (!ret) ret = nr;
	break;
	}
	ret += nr;
	if (nr != len)
	break;
	}
	out:
	if (iov != iovstack)
	kfree(iov);
	if ((ret + (type == READ)) > 0) {
	if (type == READ)
	fsnotify_access(file->f_dentry);
	else
	fsnotify_modify(file->f_dentry);
	}
	return ret;
	Efault:
	ret = -EFAULT;
	goto out;
	}

	ssize_t vfs_readv(struct file file, const struct iovec __user vec,
	unsigned long vlen, loff_t *pos)
	{
	if (!(file->f_mode & FMODE_READ))
	return -EBADF;
	if (!file->f_op \|\| (!file->f_op->readv && !file->f_op->read))
	return -EINVAL;

	return do_readv_writev(READ, file, vec, vlen, pos);
	}

	EXPORT_SYMBOL(vfs_readv);

	ssize_t vfs_writev(struct file file, const struct iovec __user vec,
	unsigned long vlen, loff_t *pos)
	{
	if (!(file->f_mode & FMODE_WRITE))
	return -EBADF;
	if (!file->f_op \|\| (!file->f_op->writev && !file->f_op->write))
	return -EINVAL;

	return do_readv_writev(WRITE, file, vec, vlen, pos);
	}

	EXPORT_SYMBOL(vfs_writev);

	asmlinkage ssize_t
	sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
	{
	struct file *file;
	ssize_t ret = -EBADF;
	int fput_needed;

	file = fget_light(fd, &fput_needed);
	if (file) {
	loff_t pos = file_pos_read(file);
	ret = vfs_readv(file, vec, vlen, &pos);
	file_pos_write(file, pos);
	fput_light(file, fput_needed);
	}

	if (ret > 0)
	current->rchar += ret;
	current->syscr++;
	return ret;
	}

	asmlinkage ssize_t
	sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
	{
	struct file *file;
	ssize_t ret = -EBADF;
	int fput_needed;

	file = fget_light(fd, &fput_needed);
	if (file) {
	loff_t pos = file_pos_read(file);
	ret = vfs_writev(file, vec, vlen, &pos);
	file_pos_write(file, pos);
	fput_light(file, fput_needed);
	}

	if (ret > 0)
	current->wchar += ret;
	current->syscw++;
	return ret;
	}

	static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
	size_t count, loff_t max)
	{
	struct file * in_file, * out_file;
	struct inode * in_inode, * out_inode;
	loff_t pos;
	ssize_t retval;
	int fput_needed_in, fput_needed_out;

	/*
	* Get input file, and verify that it is ok..
	*/
	retval = -EBADF;
	in_file = fget_light(in_fd, &fput_needed_in);
	if (!in_file)
	goto out;
	if (!(in_file->f_mode & FMODE_READ))
	goto fput_in;
	retval = -EINVAL;
	in_inode = in_file->f_dentry->d_inode;
	if (!in_inode)
	goto fput_in;
	if (!in_file->f_op \|\| !in_file->f_op->sendfile)
	goto fput_in;
	retval = -ESPIPE;
	if (!ppos)
	ppos = &in_file->f_pos;
	else
	if (!(in_file->f_mode & FMODE_PREAD))
	goto fput_in;
	retval = rw_verify_area(READ, in_file, ppos, count);
	if (retval)
	goto fput_in;

	retval = security_file_permission (in_file, MAY_READ);
	if (retval)
	goto fput_in;

	/*
	* Get output file, and verify that it is ok..
	*/
	retval = -EBADF;
	out_file = fget_light(out_fd, &fput_needed_out);
	if (!out_file)
	goto fput_in;
	if (!(out_file->f_mode & FMODE_WRITE))
	goto fput_out;
	retval = -EINVAL;
	if (!out_file->f_op \|\| !out_file->f_op->sendpage)
	goto fput_out;
	out_inode = out_file->f_dentry->d_inode;
	retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count);
	if (retval)
	goto fput_out;

	retval = security_file_permission (out_file, MAY_WRITE);
	if (retval)
	goto fput_out;

	if (!max)
	max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);

	pos = *ppos;
	retval = -EINVAL;
	if (unlikely(pos < 0))
	goto fput_out;
	if (unlikely(pos + count > max)) {
	retval = -EOVERFLOW;
	if (pos >= max)
	goto fput_out;
	count = max - pos;
	}

	retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);

	if (retval > 0) {
	current->rchar += retval;
	current->wchar += retval;
	}
	current->syscr++;
	current->syscw++;

	if (*ppos > max)
	retval = -EOVERFLOW;

	fput_out:
	fput_light(out_file, fput_needed_out);
	fput_in:
	fput_light(in_file, fput_needed_in);
	out:
	return retval;
	}

	asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t __user *offset, size_t count)
	{
	loff_t pos;
	off_t off;
	ssize_t ret;

	if (offset) {
	if (unlikely(get_user(off, offset)))
	return -EFAULT;
	pos = off;
	ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
	if (unlikely(put_user(pos, offset)))
	return -EFAULT;
	return ret;
	}

	return do_sendfile(out_fd, in_fd, NULL, count, 0);
	}

	asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t __user *offset, size_t count)
	{
	loff_t pos;
	ssize_t ret;

	if (offset) {
	if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
	return -EFAULT;
	ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
	if (unlikely(put_user(pos, offset)))
	return -EFAULT;
	return ret;
	}

	return do_sendfile(out_fd, in_fd, NULL, count, 0);
	}